I have some questions on titanium… have started experimenting with
some of that material and found a lot of trouble, and there isn=B4t
much info on books and the web… could anyone help me?

For example: What is the better way to clean the surface before
colouring? Is there any material i could use for “masking” some
parts? What material can i use for holding up the piece, that won=B4t
melt, dissipate much heat or create different colors (because of the
temperature) on the piece? Does anyone have a chart with the
temperatures for coloring titanium in a kiln? Any tips for achieving
an even colour when torch coloring? What is the effect when you
re-heat a piece that has already been colored (like, let=B4s say,
magenta temperature)? Will it continue oxidizing to the next levels
of colour? In that case, how can i get different oxidizing colours on
the same piece?

I would really appreciate any help you could give me, even site or
book advice…

Priscilla, By using a variable DC voltage power supply you can get
any color you want. If you want to mask certain areas and are using
lower voltage values <35Volts you can use nail polish. You can also
create a paint brush anodizer by connecting one lead to the ferrule
of an artist brush. Then you can paint certain portions whatever
color you want. I find I need to increase the voltage by 5 volts on
my paint brush to get the same color as the tank anodizing. This is
due to the resistance increase through the brush ferrule.

Well, you ask a lot here. Most of this is in “Studio Preparation and
Coloring of Titanium” available from RMS <reactivemetals.com>. Heat
coloring is not an exact science. Anodizing is pretictable. With
heat you have too many variables to say when or how long it will
take to get a color.

What is the better way to clean the surface before colouring?

Best is chemically. HF and nitric acids. You do not want to do it!
VERY DANGEROUS chemicals. RMS has a “MultiEtch” product that does
pretty well. Otherwise ScotchBrite is good and store in water until
you are ready to color. And keep it absolutely clean, wear gloves!

Is there any material i could use for "masking" some parts?

Any thing that won’t burn. Even particles of metal sprinkled on the
surface. Clay, ocher, white out…

What material can i use for holding up the piece, that wont
melt, dissipate much heat or create different colors (because of
the temperature) on the piece?

Make some trivets from titanium sheet or hang from a wire… That is
probably the best you can do.

Does anyone have a chart with the temperatures for coloring
titanium in a kiln?

It will depend on your kiln, preheating, the thickness of the
titanium and how it is held. Make your own chart based the equipment
you are using. It is a time/temperature relationship. Very difficult
to control.

Any tips for achieving an even colour when torch coloring?

Practice.

What is the effect when you re-heat a piece that has already
been colored (like, lets say, magenta temperature)? Will it
continue oxidizing to the next levels of colour?

The oxides gets thicker, changing the color to the higher
temperature level. So, yes, you can grow it to the next highest.
Never back to a lower.

In that case, how can i get different oxidizing colours on the same
piece?

Use a flex shaft, engraver, sand paper, whatever, to remove the
color and do a lower temperature/time color in the fresh metal. You
must remove the color and maybe some surface metal to get back to
clean material. Oxygen is absorbed into the surface of the metal. It
may look clean but color uneven due to surface absorption.

With heat, you get what you get. It is serendipity. Play, have fun
with it but try not to get too serious. Then when you get really
frustrated try anodizing. It makes all the control you are asking
for so much easier.Bill

I’ve been colouring titanium successfully for a few years and now I
have a problem. For some reason I can only get the first phase
colours (below about 40V) any higher and the colours become mottled
green/yellow/pink.

The pickling solution I use is from Oppi Untracht (4% HFl, 20% HCl
and the rest distilled water) and the electrolyte is 5% Sulphuric.

First I pickle the titanium untill it bubbles evenly, rinse (under
the tap) and then I anodise. It used to work - what could have gone
wrong?!

Many things could have gone wrong. The key is to step by step
eliminate any problems with each step in your procedure. Can you
trace it down to a specific event when it changed. What happened
just before that? I would start with the metals. Have you changed
suppliers or grades. Does old metal scrap that used to work still
work OK? Purchase all new chemicals and rebuild your baths.

I’ve been colouring titanium successfully for a few years and now I
have a problem. For some reason I can only get the first phase
colours (below about 40V) any higher and the colours become mottled
green/yellow/pink.

The pickling solution I use is from Oppi Untracht (4% HFl, 20% HCl
and the rest distilled water) and the electrolyte is 5% Sulphuric.

First I pickle the titanium untill it bubbles evenly, rinse (under
the tap) and then I anodise. It used to work - what could have gone
wrogn?!

Bill Seely will probably chime in here, but if you haven’t tried it,
take a look at his ‘Multi-Etch’. It’ll prep titanium, and doesn’t
contain any HF. Much safer. (Not to say “Harmless”, but vastly safer
than HF.) Available from Reactivemetals.com

I’ve never had that problem with anything that really was
titanium. I got a batch of mislabeled vanadium once that anodized
very oddly until I figured it out. Try sparking it, to see if it
sparks the same as a known sample of Ti. (Most of the reactives give
a bright white spark, but you may see a difference between the new
and old material. Worth the.0002 cents it costs to try anyway.)

Try anodizing a known sample of old Ti and the new stuff on the same
leads. See if there’s a difference. Equally, different grades of Ti
will anodize to different colors at the same voltages. I’ve done
things that were a mix of CP2 and CP4, and had them color
differently as part of the same piece, at the same time, in the same
bath.

You might also try a different electrolyte bath. I use Tri-Sodium
Phosphate. Available at the hardware store as a cleaning solution.
Make sure you get the real stuff. They’ve been restricting it lately
because of the phosphates. There is a “New TSP” that actually
contains no TSP. So read the ingredients. Mix it with distilled
water. I generally dump in a teaspoonfull or three into enough water
to fill the bottom of a plastic tupperware rectangular cake pan.
(There is a ‘recommended’ ratio, but I forgot it long ago. (?5%?)
Now I just do it by eye.)

The more I ponder your problem, the more it seems like the bath
breaking down. Some baths simply can’t handle the heating caused by
higher voltage, and one of the symptoms of bath breakdown is
brownish ‘burned’ looking spots, and mottling as the voltage goes
up. Did you just change your sulfuric supply or the water supply?
Acid concentration higher than you think?

You can use all sorts of things as a bath. Lemonade works, as does
Coke, but neither of them will take high voltages. All you really
need is something that’ll transmit the electricity freely, and not
break down due to localized heating. Sulfuric is a bit on the
pointlessly annoying side for that sort of job. (I was going to say
hazardous, but it isn’t really, at 5%. But you should never be
complacent with it, and there are plenty of alternatives that don’t
require that level of attention and forethought.)

Untracht was accurate when it was written, but that’s 30 years out
of date, and things have moved along a good bit since. You really
want to take a look at Bill Seely’s site, (reactivemetals.com)
and pick up a copy of his ‘how to’ pamphlet.

Here I am chiming in. First thank you for all the good words. This
is one of those times when you need to start from scratch. There are
too many variables to just nail it down. Make all new solutions,
Double check you titanium source. Test with known materials. Use a
scientific approach until find the culprit.

I prefer to clean my titanium with a steel brush on the buffing
machine. I prefer the slightly more subdued colors obtained y NOT
using Multi-etch or other etches. That said, if you are going for
brighter color, or are focusing on the higher-voltage colors (green,
royal blue, or the amazing high-voltage purple), then it seems that
Multi-Etch helps you to get those, in a clearer and more consistent
manner.

A couple other things that help with high-voltage colors: cover all
areas you are NOT coloring with tape or some other insulator,
including the back. Leave open ONLY the area you are coloring at the
moment.

Also, putting ice in the bath sometimes seems to help. I think the
spotty results I sometimes get are due to over-heating. I’m less sure
of this, since I haven’t done it a lot. But it can’t hurt to try.